This paper focuses on the active power loss minimization by optimal voltage control in a power system using a new optimization algorithm. The cost function is assumed to be convex. The algorithm we propose to address ...
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An extension to the Morison equation including Duffing oscillator-type force terms is postulated through knowledge of the flow mechanisms. This is used to curve-fit measured force time-histories from velocity time-his...
An extension to the Morison equation including Duffing oscillator-type force terms is postulated through knowledge of the flow mechanisms. This is used to curve-fit measured force time-histories from velocity time-histories, generated experimentally from various sources: regular oscillatory flow in a U-tube, cylinder oscillation in still water and in a current, random waves in the large De Voorst wave flume and a directional sea state at the Christchurch Bay Tower. The curve fits from the Morison equation are sometimes poor, while the curve fits from the extended equation are always excellent, although the corresponding 'predictions' give little or no improvement on the Morison equation. The curve fits obtained by simply adding a term proportional to F\F\, where F is force, are also significant improvements over the Morison fits enabling an improved classification of force in terms of drag, inertia and history (for each flow situation). In unidirectional flows the association of a significant history term with vortex shedding is confirmed by the occurrence of a prominent transverse or lift force. In directional seas, lift (due to vortex shedding) cannot be isolated and it is suggested that the data analysis described here will indicate the significance of vortex shedding through the relative magnitude of the history term.
In this paper, an improved algorithm for actuator-fault detection and isolation (FDI) using a bank of interval observers is presented, where each interval observer matches one considered system mode. In this approach,...
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Purpose - The purpose of this paper is to propose an automatic pattern matching template generating method for the automatic optical inspection system in TFT LCD assembly and positioning process, to improve the conven...
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Purpose - The purpose of this paper is to propose an automatic pattern matching template generating method for the automatic optical inspection system in TFT LCD assembly and positioning process, to improve the conventional image technology. Besides, focusing on integrating the image system with the existing control system, the double aligner mark searching time is decreased to reduce the working time of the integrated system. Design/methodology/approach - The improved pattern matching method of genetic algorithm was adopted, including setting for template image selecting, encoding, calculating fitness function, pattern matching, template generating and genetic algorithm steps. The predetermined pixels were selected from the target template based on the minimum difference to the block image to be tested by utilizing the genetic algorithm, and the other pixels which have not been selected were neglected. Findings - The selected pixels were encoded for recording by sequence mode, and then the target template and the image to be tested were compared based on the calculated fitness function. This method has the advantages of using the fitness function to reduce the searching time, with the help of genetic algorithm to find the optimal target template, and saving memory space by recording target template based on the sequence mode. Research limitations/implications - The genetic algorithm used in this study is a kind of optimal tool free from gradient data. As long as the fitness function and after continuous iteration are determined, the optimal solution can be found out, and then the optimal target template can be generated. Practical implications - This system uses fitness function to reduce the pattern matching time. Plural pixels are preset inside the target template, and its fitness function value is calculated. When the target template is compared with the image to be tested, only the fitness function value (also the difference of the plural pixels) is calculated
We present a technique for kernel-based identification of Wiener systems. We model the impulse response of the linear block with a Gaussian process. The static nonlinearity is modeled with a combination of basis funct...
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A novel model for identifying the traffic condition of urban arterial roadways is proposed in this paper to improve the operational efficiency and safety of the urban traffic arterial road system. During the identific...
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Overhead power transmission lines are the most damageable elements of the electric power system (EPS) [1] -[3]. An overhead power transmission line fault leads to interruption of power supply, lower quality and increa...
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ISBN:
(纸本)9781728163819
Overhead power transmission lines are the most damageable elements of the electric power system (EPS) [1] -[3]. An overhead power transmission line fault leads to interruption of power supply, lower quality and increased loss of electrical energy. To restore the normal operation of the EPS, reduce damage and costs, it is necessary to quickly and accurately locate the fault in overhead *** remote fault location (RFL) for overhead lines is an inherent function of modern substation automation systems. There are wide-spreading methods of fault location based on measurement of the emergency mode parameters (EMP) [4]. Power line currents and voltages obtained from primary converters are used as input information in the fault location methods based on *** RFL methods and devices including the methods based on EMP can be subdivided into one-sided and two-sided measurement methods. The latter use the information from both sides of power lines and also use a special communication channel between the subsets of the devices for synchronized or asynchronized data exchange [2], [4], [5]. Double-end feed lines must be equipped with RFL devices based on two-sided measurement [4] These methods have smaller error in comparison with one-sided measurement methods and measurement distortion factors (e.g. value of transient resistance in fault location) affect them to a lesser *** advantages of RFL methods based on EMP including two-sided measurement methods (for instance, compared to pulse fault location methods) are simplicity of usage, absence of generating equipment, possibility of usage in every configuration of power lines [6-8]. At the same time the RFL methods based on measuring EMP, have large (about 10-20%) error caused primarily by error of measuring units (current and voltage sensors) [1], [9]Traditional electromagnetic sensors (current (CT) and voltage transformers (VT)) have limited frequency range and error caused by core saturation. Errors of CT and VT,
The accelerating development and usage of autonomous robots has led to increased interest in decentralised systems and the cooperation of individual elements within a swarm, in particular the ability to self-organise ...
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The common, and with some exceptions the only method to interconnect high power renewable energy sources and energy storage systems to the grid has been using power electronics converters that operate as current sourc...
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ISBN:
(纸本)9781627482752
The common, and with some exceptions the only method to interconnect high power renewable energy sources and energy storage systems to the grid has been using power electronics converters that operate as current sources to the grid for the purpose of achieving the maximum primary-source power tracking. When grid is not available, such sources would not be allowed to continue operating and will be shut-down after anti-islanded algorithms recognize the loss of the grid. Although existing standards and requirements still limit grid-interface converters to regulate voltage in the grid, this functionality will inevitably be the part of the power system operation in the future. This paper addresses physical and mathematical equivalency between power electronics converters and synchronous generators, and emphasizes how an inherent synchronization feature of the synchronous generators can be used to improve the performance of the grid-interface converters. It has also been shown that if operated as a voltage source, grid-interface converter could have significant stabilizing effect on the system dynamics due to the non-delayed power delivery.
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